esp-nimble-skill

Call nimble_port_init() first, register ble_hs_cfg callbacks (sync_cb, reset_cb), register GATT services with ble_gatts_count_cfg and ble_gatts_add_svcs, then start the host task via nimble_port_freertos_init(nimble_host_task). All GAP operations must run inside the sync callback after the host synchronizes with the controller.

Define a static struct ble_gatt_svc_def array with services, characteristics, and descriptors, each tier terminated by {0}. Implement an access_cb that branches on ctxt->op for read/write operations, then call ble_gatts_count_cfg followed by ble_gatts_add_svcs before the host syncs.

NimBLE supports only Bluetooth Low Energy, including BLE 5.x features like extended advertising, periodic advertising, 2M and Coded PHY, Secure Connections, and Bluetooth Mesh. Classic Bluetooth (BR/EDR) requires the Bluedroid stack instead.

NimBLE runs on ESP32, ESP32-C3, ESP32-S3, ESP32-C2, ESP32-H2, and ESP32-H4 through ESP-IDF integration. ESP32-C3/S3/C2 use the FreeRTOS NPL port, while newer chips like ESP32-H4 use the dedicated esp-idf NPL port.

BLE_HS_EBUSY occurs when you call ble_gap_connect while a scan is still active. Call ble_gap_disc_cancel() first to stop discovery, then initiate the connection, as demonstrated in the apps/blecent example.

The service table was likely registered after host synchronization or is missing the terminating {0} entry. Ensure ble_gatts_count_cfg and ble_gatts_add_svcs run before nimble_port_freertos_init, and that every service, characteristic, and descriptor array ends with {0}.